ENVIRONMENTAL ENGINEERING - Introduction to Soft Soil Geotechnique: Content, Context and Application - page 225

14 ENVIRONMENTAL ENGINEERING
Environmental engineering in the geotechnical profession can be seen as a part
of eco-engineering or geo-engineering, which has become a new and important
topic to retain the best possible living ambience on earth. The vastly increasing
population and its affluence and technology is affecting the earth on a global scale,
and if no changes occur, humans could become the reason of a sixth catastrophic
mass extinction of plants and animals. Geologists debate to refer to this global
impact as a new geological period: the Anthropocene. A fact is that humans are
transforming the world and altering the planet through farming (40% of the land is
used for agriculture) and by building cities (soon 80% of the expected 9 billion
humans will live in large metropoles in fertile and vulnerable lowland areas). In a
lecture about eco-engineering in 2010, Rijnaarts showed that the balance of
depletion and accumulation in the natural biological system is at stake: the fresh
water cycle is for 65% exhausted, the phosphorus cycle for 82%, the CO 2 cycle is
with 110% beyond its balance boundary and nitrogen even with 400%, while the
status of chemical pollution and the carbon balance are not known. Important
minerals, like phosphor, may become extinct bringing life in real danger. There is
hope that with growing awareness also readiness for a drastic change of human
habits will increase.
The ground is an important buffer, a flywheel of society's wealth. Its protection
is vital and geotechnical engineers should contribute their part in preserving the
best conditions, in particular when building cities and their infrastructure and when
exploiting transport processes in the underground. Environmental engineering in
the geotechnical field usually considers the impact of (underground) construction
to the surroundings (Chapter 15) and pollution of the underground, i.e.
contamination of the ground, hazardous to flora and fauna (this Chapter).
It is not easy to distinguish pollution amongst the many natural processes that
take place, more so as most are beneficial for controlling ground functions in a way
to stimulate health and life in upper soil. The air and water in soil are volatile, but
ground itself is solid. The knowledge of physical, chemical and biological
interactions in the underground is important in order to understand not so much the
presence of contaminants, but rather their effect. In environmental engineering, the
effect of (human) action on the main functions of ground are studied. These
functions are agriculture (food), filter (groundwater) and ecology (bio-cycles). Air
pollution (heavy metals), water pollution (rivers), or solid pollution (dung, dump,
spill, leakage) are widespread threats to the local ground quality. A modern way of
treating polluted areas is Flexible Emission Control (Van Meurs) that involves
impact containment and stimulation of natural bio-chemical cleansing.
A PHYSICAL - CHEMICAL CHARACTERISTICS OF SOIL
The upper soil can be considered as a three-phase system: solid, liquid and gas.
The global average distribution of these components is: air 26%, water 24%,
organic matter 5% and minerals 45%. In deltaic areas this distribution is different:
air 5%, water 33%, organic matter 7% and minerals 55%. In these sedimentary